
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var age= 18;
       var  age = window.prompt('你多大？？');
       document.write(`我今年${age}岁了`);
    </script>
</body>
</html>